Movement of a working station with reference to a substantially vertical surface

ABSTRACT

Arrangement for moving a working station with reference to a substantially vertical surface, particularly the external surface of a ship hull. A vehicle is advanced in a horizontal path adjacent to and along the surface and a working station, movably supported on the vehicle, is simultaneously moved in a substantially vertical path with reference to the travelling vehicle between an upper and a lower end position whereby it moves along a substantially vertical strip of the surface. On reaching one or the other of its end positions, the working station is rapidly shifted in the direction of advancement of the vehicle and thereupon again moved in a substantially vertical path with reference to the travelling vehicle along another substantially vertical strip of the surface which is directly adjacent to but does not overlap over the first vertical strip.

United States Patent 1191 Hammelmann 11 1 3,783,819 Jan. 8, 1974 [76] lnventor: Paul Hammelmann, Zum Sundem 17, Oelde/Westfalen, Germany [22] Filed: Nov. 12, 1970 [21] Appl. No.: 88,722

Related US. Application Data [62] oiViS'i'SHd'r' ser'. No. 803,126, Feb. 26, 1969, Pat.-

118/323, 109; 15/21 E, 21, DIG. 2, 405; 114/222; 117/104 R; 239/1; 134/42 [56] References Cited UNITED STATES PATENTS 3,196,472 7/1965 Ventrella 14/21 E 3,104,406 9/1963 Rhodes 15/21 E 3,224,108 12/1965 Flaming 15/DIG. 2 3,460,177 8/1969 Rhenehart et al..... 15/21 E 3,439,372 4/1969 Collier 15/21 E 2,444,811 7/1948 Crom 118/305 X 667,369 2/1901 Redman... 118/305 1,079,208 11/1913 Brownem. 114/222 2,098,262 11/1937 Temple.... 118/207 X 3,099,852 8/1963 Grant 15/21 E X 3,442,027 5/ 1969 Hurwitz 15/405 X Primary Examiner-John P. McIntosh Attorney-Michael S. Striker [57] ABSTRACT Arrangement for moving a working station with reference to a substantially vertical surface, particularly the external surface of a ship hull. A vehicle is advanced in a horizontal path adjacent to and along the surface and a working station, movably supported on the vehicle, is simultaneously moved in a substantiallyvertical path with reference to the travelling vehicle between an upper and a lower end position whereby it moves along a substantially vertical strip of the surface. On reaching one or the other of its end positions, the working station is rapidly shifted in the direction of advancement of the vehicle and thereupon again moved in a substantially vertical path with reference to the travelling vehicle along another substantially vertical strip of the surface which is directly adjacent to but does not overlap over the first vertical strip.

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INVENTOR PAUL HAMMELMANN MOVEMENT OF A WORKING STATION WITH REFERENCE TO A SUBSTANTIALLY VERTICAL SURFACE CROSS-REFERENCE TO RELATED APPLICATION This application is a division of my co-pending application, Ser. No. 803,126, now U.S. Pat. No. 3,623,902 filed Feb. 26, 1969, entitled Movement of a Working Station with Reference to a Substantially Vertical Surface."

BACKGROUND OF THE INVENTION The present invention relates to the movement of a working station with reference to a substantially vertical surface. More specifically, the invention relates to such a movement for the purpose of inspecting or treating the surface.

In particular, the invention relates to an arrangement for inspecting or treating large substantially vertical surfaces, particularly the external surface of the hull of a watercraft.

It is well known that it is frequently necessary to treat the external surface of the hull of watercraft, either for cleaning to remove barnacles, or for applying protective coatings such as paint, rust preventives or the like. Hand in hand with this necessity goes the requirement for close-up inspection of such surface. It is appropriate to point out at this juncture that, while the invention is hereafter to be discussed with respect to the external surfaces of watercraft hulls, it is fully applicable to other large substantially vertical surfaces and that its application for use on watercraft hulls is merely a particularly advantageous example of use.

Returning to the treatment of the external surfaces if watercraft hulls, it is pointed out that .it is already known to clean such hulls by directing against their external surfaces a stream of water under pressures which range between substantially 150 and 200 atmospheres. However, this known approach to the problem of cleaning requires that the operator manipulating the discharged nozzle be capable of approaching the surface, or more particularly the surface area to be cleaned, within approximately two meters. Where larger ships are involved, that is ships in excess of approximately 5,000 tons, this necessitates the special construction of scaffolding or other supporting devices to make it possible for the operator to approach the hull surface to the requisite extent. This, however, is expensive and time-consuming; in fact, the erection of the scaffolding or analogous supports quite often requires an amount of time which is a multiple of the actual working time needed for the cleaning of the hull surface.

It is evident, then, that improvements in this field are most desirable. At this time it need not be particularly pointed out what has been said above with respect to the cleaning of external surfaces of watercraft hulls is fully applicable also with reference to any inspection which must be carried out at close range or with the application of protective-coatings, such as paint or the like. 1

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to overcome the aforementioned disadvantages.

More particularly, it is an object of the present invention to provide an arrangement for treating and/or inspection of large substantially vertical surfaces which is considerably simpler than heretofore known and which does not require the erection of special supports.

An additional object of the invention is to provide such an arrangement which, because it does not rely on the erectionof supports, permits the time required for carrying out the necessary steps to be decreased significantly, and thereby enables a correspondingly signifi cant reduction in the expenses involved in carrying out these steps.

In pursuance of the above objects, and others which will become apparent hereafter, one feature of my invention resides in an arrangement having a working station which is movably supported on a vehicle, and

which is moved with reference to a substantially verti cal surface, particularly with reference to the external surface of the hull of a watercraft.

According to my invention, I advance the vehicle, on which the working station is movably supported, in a horizontal path adjacent to and along the-surface in question, and I simultaneously move the working station in a substantially vertical path with reference'to the travelling vehicle between an upper and a lower end position. In this manner, the working station moves along a substantially vertical strip of the surface in one substantially vertical direction. When the working station reaches a respective one of its end positionspit is rapidly shiftedin the direction of advancement of the vehicle by a distance corresponding to the width of the substantially vertical strip and thereupon the working station is again moved in a substantially vertical path with reference to the travelling vehicle but in the opposite vertical direction whereby it moves along an addi? tional substantially vertical strip of the surface which is adjacentto the first-mentioned strip but does not overteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects-and advantages thereof, will be best understoof from the following-description of specific embodiments when read in connection with 4 the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view, in diagrammatic illustration, of an arrangement for carrying out my invention and showing the working station in its upper end position;

FIG. 2 is an end view of FIG.-1;

FIG. 3 is a view similar to FIG. 2, but showing the arrangement with the working station in its lower end position;

FIG. 4 is a fragmentary detailed view of FIG. 3, showing on an enlarged scale;

FIG. 5 illustrates, on an enlarged scale, detailsof the arrangement of the working station at the upper end portion of the mast of FIG. 1, but with the mast in retracted position;

FIG. 6 is a top plan view of FIG. 5;

FIG. 7 is a detailed view, on an enlargedscale and in side view,.of the joint connecting the mast sections with one another;

FIG. 8 is a plan view of FIG. 7

FIG. 9 is a diagram illustrating the hydraulic circuits of the embodiments shown in FIGS. 1-7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail, it will be seen that in FIG. I I have illustrated a vehicle 1 having a frame or chassis 2. The chassis carries a console 9 of known construction and on this console there is mounted the lower section 4 of a collapsible mast consisting of two sections, namely the lower section 4 and the upper section 5. As shown in FIG. 1 in particular, the lower section 4 is mounted with its lower end on the console 9 turnable about an axis which extends transversely to the elongation of the vehicle 1, and accordingly transversely to its direction of movement. The mast 4, 5 is further turnably tiltable about a horizontal axis 8 which extends in parallelism with the elongation of the vehicle 1 and therefore with its direction of movement. A suitable engine, such as a diesel engine 11, is provided on the frame 2 and serves to drive in the illustrated embodiment a high pressure pump 12, as well as a non-illustrated compressor and othe nonillustrated components. The vehicle 1 further comprises a rear or drive axle 13 which is hydraulically driven, with the pressure fluid being preferably oil, and a front or a steering axle 14, as well as a control cockpit 15.

In addition, I may provide on the vehicle 1 a waterbath which is heatable in suitable manner and is not illustrated because it is conventional. The purpose of this is to heat materials, such as rust-proofing or other protective materials, which are to be sprayed onto a surface being treated. In this manner it is assured that these materials have the requisite viscosity independently of the prevailing ambient temperature, and this in turn guarantees that when they are applied to a surface the protective layer obtained will have the requisite thickness.

The mast sections 4 and 5 have associated withthem parallel guidance members 6 and 7 of known construction.

The upper end of the mast section 5 carries the working station which is preferably and ordinarily constructed either as a high pressure nozzle from which cleaning fluid, such as water, is ejected at high pressure against the surface to be treated, or as a spray nozzle for paint or other protective substances, such as rustproofing materials. However, it is possible to construct the working station as a so-called gondola or bucket in which an operator may be carried along the surface for inspection and/or working purposes. In the illustrated embodiment, I have shown the working station to be constructed as a tubular high pressure ejection nozzle 16 through which water is to be ejected at high pressure against the surface for cleaning purposes. The nozzle 16 is mounted on a supporting tube 17 for movement to and fro. The supporting tube 17 in turn carries at its opposite ends rollers 18 and 19 which co-operate with the surface being treated. It is carried on a jib 20 which is mounted on the upper end of the mast section 7 for turning movement about a vertical axis 21.

As shown in FIG. 4, the illustrated embodiment further provides a transverse jib 22 whose free end is provided with a sliding sleeve 23 which surrounds a guide rod 24 extending parallel to the nozzle 16 to which latter the transverse jib 22 is connected. The purpose of this arrangement I is to compensate for the reaction forces acting upon the nozzle 16 when water is ejected therefrom at high pressure. An additional tube 26 is connected to the guide rod 24 via connecting members 25 and cooperates with the rollers 27 which are provided on the sliding sleeve 23, as shown in FIG. 5. The purpose of these rollers is to limit the freedom of movement of the nozzle 16. However, it should be understood that the provision of the additional tube 26 with the rollers 27 is optional and my novel arrangement will be operative without it.

I have found it advantageous to construct the transverse jib 22 as a pressure cylinder which is acted upon by the high pressure water being used for cleaning purposes and is so constructed that it is capable of compensating for most of the reaction force resulting from the ejection of the high pressure water from the nozzle 16. The constructionof the transverse jib 22 in this manner imparts to the manner in which the nozzle 16 is mounted a certain compensatory ability which gurantees uniform spacing from the surface. It will be appreciated that this is advantageous because of the inertia of the masses to be moved, the unevenesses of the surface to be cleaned or treated, and in the ground on which the vehicle moves, as well as the inertia of the sensing device which is to be described and which serves primarily to effect constant spacing of the working station from the surface being treated.

The just-mentioned sensing device is illustrated clearly in FIG. 6 where it will be seen in the present embodiment to include a feeler 28 which cooperates with the surface (see also FIG. 4 where the surface is shown as the external surface of a watercraft hull) and which serves to actuate the drive which effects tilting of the mast 4, 5 about the axis 8. It should be remembered that this axis 8 extends in substantial parallelism with the surface to be treated because it is parallel to the path along which the vehicle 1 advances, and this path is of course parallel to the surface. In the illustrated embodiment, the drive for tilting of the mast 4,5 about the axis 8 is a hydraulic cylinder 29 as shown in FIG. 2, which is connected with a console 30 which latter is in turn rigid with the console 9. The extent to which the hydraulic cylinder 29 can tilt the mast 4,5 about the axis 8 is illustrated in dashed lines in FIG. 2 and makes the illustrated arrangement simple on all types of ship hulls. Of course, the illustrated tilting angles can be readily changed and how this is accomplished will be obvious to those skilled in the art.

The actual cooperation between the feeler 28 and the hydraulic cylinder29 will be discussed below with respect to FIG. 9. However, it will be apparent already that the feeler guarantees that the working station will always be at a predetermined distance from the surface being treated, and of course this distance may be zero if this should be desired, in which latter case the rollers associated with the nozzle 16, or the nozzle 16 itself, may be in direct contact with the surface, as for instance as shown in FIG. 4.

As the vehicle 1 moves at constant speed in its horizontal path along the surface to be treated, the mast must be alternately collapsed and upwardly extended. In the illustrated embodiment, this is achieved via the hydraulic cylinder 31 illustrated in FIG. 1 and reversal of movement of the mast sections 4 and 5 with respect to one another, that is reversal of movement as the mast sections reach respectively the upper and lower end positions, is controlled via limit switches 32 and 33 which cooperate with cams 35 and 36 adjustably arranged on a disc 37 which is rigidly connected with the lower end of the mast section 4, as illustrated in FIG. 1.

In operation of the arrangement, the vehicle 1 advances in its aforementioned horizontal path at constant speed and the mast sections 4 and 5 are constantly collapsed and erected. The parallel guidance members 6 and 7 serve to assure that the working station remains horizontal during this movement. If the general plane of the surface being treated is not entirely vertical but is inclined towards away from the path along which the vehicle 1 advances, then the feeler 28 generates a signal which actuates the hydraulic cylinder 29 via which the mast 4,5 is tilted about the axis 8 in the sense indicated by the broken lines of FIG. 2, that is to one or the other side of the horizontal path along which the vehicle l advances. During the upward or downward movement of the mast sections 4,5 and the advancement of the vehicle 1, the working station is moved by advancing means (see FIG. 9) in the direction opposite the direction of advancement of'the vehicle 1 with a speed corresponding to the speed of advancement of the vehicle. Thus, the working station remains stationary with respect to the surface being treated, except for movementin vertical direction relative to the surface.

As the working station reaches its upper and lower end positions, shifting means (see FIG. 9) shifts it in the advancement direction at a higher speed than that of the vehicle by a distance corresponding to the width of the upright strip of the surface which it has just finished treating.

A compensating arrangement is provided for compensating for the weight of the upper mast section 5. This is illustrated in FIG. 7 and includes a hollow shaft 38 rigidly connected with the lower end of the mast section 5 and having connected thereto an eccentric disc 39. A flexible draft member 40 partially or completely is convoluted about the periphery of the disc 39 to which it is connected with one of its ends, whereas its other end is connected to a drawing device 41 which in the illustrated embodiment is configurated as a hydraulic cylinder secured to the mast section4. When the mast is collapsed, as shown in FIG. 7, the eccentric disc has the longest lever arm with respect to the drawing device 41 whereas, when the mast is erected as in FIG. 1, it has the smallest lever arm. This arrangement serves to assist the parallel guidance member 6 which therefore can be of rather light construction and this, in turn, makes it possible to hold the tilted mass of the mast at a lower level than would otherwise be feasible.

It will be appreciated from what-has already been stated'that the major functions of the arrangement are hydraulically controlled. This includes extending and collapsing of the mast, advancing of the vehicle 1, con-- tinuous movement of the working station with respect to the advancement of the vehicle and maintenance of the working station at a predetermined distance from the surface to be treated, which distance may be zero.

FIG. 9 shows the hydraulic connections involved. I provide a gear pump 42 which is protected from overloading by a relief valve 43 which in the illustrated embodiment is set for approximately kp/cm". Cylinders 3] and 41 serve to effect extending and collapsing of the mast..An adjustable valve 44 serves to regulate the speed of the upward movement of the mast, that is the movement to the erected position thereof. An auxiliary cylinder 41 serves to aid in the erection of the mast sec- A four-way valve 46, which may be manually activated or else automatically via the limits which is 32 and 33 which are secured on the joint 9, serves to initiate the movement from the lower end position towards erected position, and vice versa. Cams 35 and 36 provided on the disc 37 limit the stroke or lift during such movement of the mast. The automatic actuation via the limit switches 32 and 33 makes it possible to arrest the mast for approximately one-half second in its respective upper and lower end positions while the magnetic valve 47 is actuated and the nozzle 16 shifted to oppposite position by compressed air.

During movement of the vehicle 1, the oil pump 48, which is rigidly coupled with the oil drive motor 49, serves to move the nozzle 16 at the same speed as the vehicle 1 but in opposite direction to the direction of advancement of the vehicle, the valve 47 being closed at this time. The oil drive motor 49 is fed via manually activated four-way valve 50 which enables control of the vehicle movements between a standing position, a forward movement and a backward movement. An adjustable valve 51 makes possible a continuously variable speed adjustment. A change-over gear is arranged between the drive motor 49 and the differential axis of the vehicle 1,. and makes possible the movement of the vehicle at two different speeds. The working station may in the illustrated embodiment be pressed against the surface to be treated with a pressure of approximately 20 kp which is automatically maintained. The cylinder 29 is always fully pressurized on the small surface, and also the cylinder 52 of the feeler 28. The control bore 53 serves for pressurizing the larger cylinder area, so that a predetermined regulatable spacing of the mast is always obtained with a predetermined contact pressure which is determined through the pressurized surfaces of the cylinder. A valve 54 is provided which, when closed, makes possible manual tilting of the mast about the axis 8 with the help of the three-way valve 55.

It will be appreciated, as already pointed out earlier, that the high pressure nozzle 16 may be replaced by a spray nozzle for spraying paint or other protective substances onto the surface, and that in place of either ofthese possibilities a bucket or gondola may be mounted for carrying an operator for repair and/or inspection purposes.

It should be pointed out that in the illustrated embodiment the mast sections 4 and 5 are constructed in lattice or grid fashion and composed of tubular members. The use of tubular members makes it possible to avoid the necessity for separate hoses or conduits supplying water, paint or the like to the working station be cause certain of the tubular members of the mast sections 4 and 5 may be made to communicate with one another and the materials to be supplied to the working station, that is here the nozzle 16, may be advanced through these communicating tubular members which thus serve as a supply conduit. This of course eliminates the use of separate conduits and for complicated guidance and support arrangements therefor, and further simplifies the construction with attending economies.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the inventionv has been illustrated and described as embodied in an arrangement for treating or inspecting the external surface of a ships hull, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of this invention, and therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims is:

1. An arrangement for moving a working station with reference to a substantially vertical surface, particularly with reference to the external surface'of the hull of a watercraft, comprising a vehicle operative for travel in one direction along and proximal to said surface in a horizontal path and at a constant first speed; a working station; mounting means mounting said working station on said vehicle for movement in an upright path with reference to said vehicle between an upper and a lower end position and along an upright strip of said surface during advancement of said vehicle; advancing means for advanacing said working station with reference to said vehicle at said constant first speed but in another direction opposite to said one direction; shifting means for shifting said working station in said one direction at a second speed higher than said first speed during travel of said vehicle in said one direction, by a distance corresponding to the width of said substantially vertical strip and when said working station arrives at the respective end positions thereof; an elongated high-pressure nozzle on said working station mounted for to-and-fro movement in a path substantially parallel to said horizontal path for expulsion of treating fluid with a concomitant development of reactive forces; and compensating means comprising a jib secured to said elongated nozzle extending transversely thereto and having a free end remote therefrom, a guide member mounted on an upper most section in parallelism with said nozzle, and a sleeve slidably surrounding saidguide member.

2. An arrangement as defined in claim 1, said compensating means comprising a hydraulic cylinder-andpiston arrangement operatively associated with said mast and said nozzle.

3. An arrangement as defined in claim 1, said compensating means further comprising an additional tubular guide member parallel to the first-mentioned tubular guide member spaced therefrom, and roller means provided on said sleeve and engaging said additional tubular guide member for rolling movement therealong.

4. An arrangement for moving a working station with reference to a substantially vertial surface, particularly with reference to the external surface of the hull of a watercraft, comprising a vehicle operative for travel in one direction along and proximal to said surface in a horizontal path and at a constant first speed; a working station; mounting means mounting said working station on said vehicle for movement in an upright path with reference to said vehicle between an upper and a lower end position and along an upright strip of said surface during advancement of said vehicle, said mounting means including a mast having an upper and a lower mast section; advancing means for advancing said working station with reference to said vehicle at said constant first speed but in another direction opposite to said one direction; shifting means for shifting said working station in said one direction at a second speed higher than said first speed during travel of said vehicle in said one direction, by a distance corresponding to the width of said substantially vertical strip and when said working station arrives at the respective end positions thereof; and counterbalancing means for at least substantially counterbalancing the weight of said upper mast section, including a tubular shaft rigid with said lower end of said upper section, a disc-shaped eccentric mounted on said tubular shaft, elongated flexible means convoluted about at least a part of the periphery .of said disc-shaped eccentric and having a first end connected thereto and a free second end, and drawing means connected with said second end and with said lower section and being operative for exerting a requisite drawing force on said flexible means.

;5. An arrangement as defined in claim 4, said drawing means being a hydraulic drawing cylinder-andpiston arrangement.

6. An arrangement for moving a working station with reference to a substantially vertical surface, particularly with reference to the external surface of the hull of a watercraft, comprising a vehicle operative for travel in one direction along-and proximal to said surface in a horizontal path and at a constant first speed; elongated mounting means having a lower end mounted on said vehicle and having an upper end adapted to move in an upright path with reference to said vehicle between a lower and an upper end position and along an upright strip of said furface during ad vancement of said vehicle; means for raising and lowering said upper end of said mounting means relative to said vehicle between said lower and upper end positions; a working station mounted on said upper end of said mounting means movable to and fro with respect to said mounting means in a substantially horizontal direction; advancing means for advancing said working station during movement of said vehicle at said constant first speed with reference to said mounting means at a constant first speed but in a direction opposite to said one direction; and shifting means for shifting said working station in said one direction at a second speed higher than said first speed by a distance corresponding to the width of said upright strip, when said upper end of said mounting means together with said working station arrives at the respective end positions thereof.

7. An arrangement as defined in claim 6, said mounting means including a mast having an upper and a lower mast section, said lower mast section having a lower end connected to said vehicle for tilting movement about a first horizontal axis parallel to said horizontal path and to said surface, and an upper end connected to the lower end of said upper section for tilting movement about a second horizontal axis normal to said horizontal path and surface.

8. An arrangement as defined in claim 7, said upper section having an upper end, and said working station being mounted on and carried by said upper end of said upper section.

9. An arrangement as defined in claim 7, said lower mast section also being connected to said vehicle for tilting movement about a third horizontal axis extending parallel to said horizontal path and to the general plane of said surface.

10. An arrangement as defined in claim 9; further comprising sensing means provided on said mast and operative for sensing the distance of said working station from said surface; and actuating means operatively associated with said sensing means and said mast for tilting the latter about said third axis in response to signals originating at said sensing means and to the extent requisite for maintaining said working station at a pre- I section for turning movement about a vertical axis, and said nozzle being mounted on said support member for said to-and-fro movement.

14. An arrangement as defined in claim 12; further comprising a supply of treating fluid provided on said vehicle for injection from said nozzle; and conduit means connecting said nozzle with said supply.

15. An arrangement as defined in claim 12, the expulsion of treating fluid at high pressure from said nozzle resulting in concomitant development of reaction forces; and further comprising compensating means associated with said nozzle and operative to compensate for said reaction forces.

16. An arrangement as defined in claim 7; and further comprising counterbalance means associated with said sections for at least substantially counterbalancing the weight of said upper section.

17. An arrangement as defined in claim 7, said sections each being composed of a plurality of connected tubular elements arranged in a lattice-work construction.

18. An arrangement as defined in claim 17, said working station including a fluid-ejecting device, and each of said sections having at least a tubular element communicating with the interior of a tubular element of the other section and together communicating with said fluid-ejecting device so as to constitute a fluid supply conduit'for the same.

19. An arrangement asdefined in claim 6, said working station comprising at least one spray device for spraying a coating material onto said surface. 

1. An arrangement for moving a working station with reference to a substantially vertical surface, particularly with reference to the external surface of the hull of a watercraft, comprising a vehicle operative for travel in one direction along and proximal to said surface in a horizontal path and at a constant first speed; a working station; mounting means mounting said working station on said vehicle for movement in an upright path with reference to said vehicle between an upper and a lower end position and along an upright strip of said surface during advancement of said vehicle; advancing means for advanacing said working station wiTh reference to said vehicle at said constant first speed but in another direction opposite to said one direction; shifting means for shifting said working station in said one direction at a second speed higher than said first speed during travel of said vehicle in said one direction, by a distance corresponding to the width of said substantially vertical strip and when said working station arrives at the respective end positions thereof; an elongated high-pressure nozzle on said working station mounted for to-and-fro movement in a path substantially parallel to said horizontal path for expulsion of treating fluid with a concomitant development of reactive forces; and compensating means comprising a jib secured to said elongated nozzle extending transversely thereto and having a free end remote therefrom, a guide member mounted on an upper most section in parallelism with said nozzle, and a sleeve slidably surrounding said guide member.
 2. An arrangement as defined in claim 1, said compensating means comprising a hydraulic cylinder-and-piston arrangement operatively associated with said mast and said nozzle.
 3. An arrangement as defined in claim 1, said compensating means further comprising an additional tubular guide member parallel to the first-mentioned tubular guide member spaced therefrom, and roller means provided on said sleeve and engaging said additional tubular guide member for rolling movement therealong.
 4. An arrangement for moving a working station with reference to a substantially vertial surface, particularly with reference to the external surface of the hull of a watercraft, comprising a vehicle operative for travel in one direction along and proximal to said surface in a horizontal path and at a constant first speed; a working station; mounting means mounting said working station on said vehicle for movement in an upright path with reference to said vehicle between an upper and a lower end position and along an upright strip of said surface during advancement of said vehicle, said mounting means including a mast having an upper and a lower mast section; advancing means for advancing said working station with reference to said vehicle at said constant first speed but in another direction opposite to said one direction; shifting means for shifting said working station in said one direction at a second speed higher than said first speed during travel of said vehicle in said one direction, by a distance corresponding to the width of said substantially vertical strip and when said working station arrives at the respective end positions thereof; and counterbalancing means for at least substantially counterbalancing the weight of said upper mast section, including a tubular shaft rigid with said lower end of said upper section, a disc-shaped eccentric mounted on said tubular shaft, elongated flexible means convoluted about at least a part of the periphery of said disc-shaped eccentric and having a first end connected thereto and a free second end, and drawing means connected with said second end and with said lower section and being operative for exerting a requisite drawing force on said flexible means.
 5. An arrangement as defined in claim 4, said drawing means being a hydraulic drawing cylinder-and-piston arrangement.
 6. An arrangement for moving a working station with reference to a substantially vertical surface, particularly with reference to the external surface of the hull of a watercraft, comprising a vehicle operative for travel in one direction along and proximal to said surface in a horizontal path and at a constant first speed; elongated mounting means having a lower end mounted on said vehicle and having an upper end adapted to move in an upright path with reference to said vehicle between a lower and an upper end position and along an upright strip of said furface during advancement of said vehicle; means for raising and lowering said upper end of said mounting means relative to said vehicle between said lower and upper end posItions; a working station mounted on said upper end of said mounting means movable to and fro with respect to said mounting means in a substantially horizontal direction; advancing means for advancing said working station during movement of said vehicle at said constant first speed with reference to said mounting means at a constant first speed but in a direction opposite to said one direction; and shifting means for shifting said working station in said one direction at a second speed higher than said first speed by a distance corresponding to the width of said upright strip, when said upper end of said mounting means together with said working station arrives at the respective end positions thereof.
 7. An arrangement as defined in claim 6, said mounting means including a mast having an upper and a lower mast section, said lower mast section having a lower end connected to said vehicle for tilting movement about a first horizontal axis parallel to said horizontal path and to said surface, and an upper end connected to the lower end of said upper section for tilting movement about a second horizontal axis normal to said horizontal path and surface.
 8. An arrangement as defined in claim 7, said upper section having an upper end, and said working station being mounted on and carried by said upper end of said upper section.
 9. An arrangement as defined in claim 7, said lower mast section also being connected to said vehicle for tilting movement about a third horizontal axis extending parallel to said horizontal path and to the general plane of said surface.
 10. An arrangement as defined in claim 9; further comprising sensing means provided on said mast and operative for sensing the distance of said working station from said surface; and actuating means operatively associated with said sensing means and said mast for tilting the latter about said third axis in response to signals originating at said sensing means and to the extent requisite for maintaining said working station at a predetermined distance from said surface.
 11. An arrangement as defined in claim 10, said actuating means and said sensing means each comprising hydraulic means.
 12. An arrangement as defined in claim 9, said working station comprising an elongated high-pressure nozzle mounted for to-and-fro movement in a path substantially parallel to said horizontal path and arranged for expulsion of a treating fluid at high pressure against said surface.
 13. An arrangement as defined in claim 12, said working station further comprising an elongated support member mounted on said upper end of said upper section for turning movement about a vertical axis, and said nozzle being mounted on said support member for said to-and-fro movement.
 14. An arrangement as defined in claim 12; further comprising a supply of treating fluid provided on said vehicle for injection from said nozzle; and conduit means connecting said nozzle with said supply.
 15. An arrangement as defined in claim 12, the expulsion of treating fluid at high pressure from said nozzle resulting in concomitant development of reaction forces; and further comprising compensating means associated with said nozzle and operative to compensate for said reaction forces.
 16. An arrangement as defined in claim 7; and further comprising counterbalance means associated with said sections for at least substantially counterbalancing the weight of said upper section.
 17. An arrangement as defined in claim 7, said sections each being composed of a plurality of connected tubular elements arranged in a lattice-work construction.
 18. An arrangement as defined in claim 17, said working station including a fluid-ejecting device, and each of said sections having at least a tubular element communicating with the interior of a tubular element of the other section and together communicating with said fluid-ejecting device so as to constitute a fluid supply conduit for the same.
 19. An arrangement as deFined in claim 6, said working station comprising at least one spray device for spraying a coating material onto said surface. 